1. Field of the Invention
The invention relates to a device for coupling at least two spacecraft by means of a tether or cable connection and the use of such a device for repairing tether damage.
2. Description of the Prior Art
In U.S. Pat. No. 4,824,051, a device for coupling two spacecraft is described in which a cable is provided as coupling means.
Additional damage risks are encountered when using tether technology in space travel due to the particular system configuration, for example due to the exposed cable area per unit time. A particular risk is represented by a cable severance due to technical or mechanical defects, dynamic instabilities or ambient conditions, for example in the form of natural and/or artificial objects in space, chemical reactions with the atmosphere or the influence of radiation, which can lead to total loss of the mission.
With the monotethers used hitherto, after tether severance due to the effects of orbital mechanics, reestablishing the original tether configuration is possible, if at all, only with extremely great technical expenditure.
So far, in experimental orbital preliminary tests, for tether technology monocables were used, for example in conjunction with Gemini 11. Furthermore, in the first scientific tether missions, for example in the TSS-1 program, once again only conductive or non-conductive monocables were employed. Within the framework of the aforementioned TSS-1 program, theoretical investigations were made with regard to an inspection and possible repair of damaged monocable tethers.
An estimation of the probability of a cable severance (with up to five possible severances per year) showed that due to such tether severances the risk of a space mission is unacceptable high. In many applications planned, severance of a monocable could possibly lead to the loss of at least one of the tethered systems, By overdimensioning the diameter of a monocable, the cable mass is increased by the square thereof without thereby reducing the cable severance probability to the same extent. For this reason, with the concepts of tether technology used and proposed today in space travel, only short missions are possible.
As already stated, in the event of tether severance reestablishment of the tether configuration is possible only with very great effort and the resulting high costs, due to the diverging orbital paths of the separate space systems resulting high costs, due to the diverging orbital paths of the separate space systems resulting from tether severance, this in turn being due to the gravity gradient forces.